Atypical Myopathy

Now that Autumn has taken hold, trees are shedding leaves and the weather has changed from sunny to windy make yourself aware of the risks and symptoms of Atypical Myopathy.

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Sycamore SeedsAtypical Myopathy or Seasonal Pasture Myopathy is a rare but important disease of horses that is seen with increasing frequency especially during autumn months.

Research regarding the cause of this potentially fatal condition gives owners the opportunity to reduce the risks of the development of this disease. Early recognition of the signs remain vital so that you can obtain veterinary advice should you horse become unwell

Which Horses Does It Affect?

Atypical myopathy affects younger horses, especially those under three years of age, thin, not in regular work and kept on sparse pastures without supplemental feeding. The condition is caused by a pasture based toxin and therefore can affect several or all horses on a pasture. The disease causes severe muscle damage resulting in:

  • Severe generalised weakness and stiffness, leading to muscle tremor and potentially collapse
  • Decreased appetite and colic like signs
  • Dark coloured urine.

Treating Atypical Myopathy

Although the disease can be fatal, intensive early treatment maximises chances of survival. If you suspect the condition you should attempt to remove your horse from the pasture. Contact your veterinary surgeon as soon as possible. If you have the opportunity to obtain a urine sample (in a cup, bucket etc.) this will assist your veterinary surgeon in making a diagnosis.

Based on the high fatality rate of the disease, staff within the practice will need to hospitalise your horse in the clinic on Markeaton Lane, Derby in order to provide the intensive therapy needed. This will include intravenous fluids and intravenous nutrition and a range of pain killers.

Causes Of Atypical Myopathy

Research carried out within the last 12 months has shown that atypical myopathy is caused by a toxin (Hypoglycin A) in the ‘helicopter’ seeds of the sycamore tree (Acer pseudoplatanus). The warm summer and early autumn has seen an abundance of seeds within sycamore trees.

If your horse grazes on pasture surrounded by sycamore trees or if large numbers of seeds blow into the field you should:

  • Consider fencing off areas around trees
  • Remove sycamore seeds
  • Supply extra hay especially if the pasture quality is poor; horses will not chose to eat the seeds if there is sufficient grass
  • Reduce stocking density within pastures
  • Stable horses and turn out for short periods of time.

Act now: walk around your horse’s field and identify whether sycamores surround its field.

Please contact us urgently if you suspect Atypical Myopathy on 01332 294929.

Out of hours emergency

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